Methods and devices for enabling reception of beam sweep transmissions

ABSTRACT

There is disclosed a method performed by a wireless communication device 100 to enable the reception of a beam sweep transmission. The method comprises obtaining S1 information enabling said wireless communication device 100 to determine whether it is stationary, or essentially stationary. The method also comprises acquiring S2 configuration information comprising information about the starting time for the beam sweep transmission. The method also comprises determining S3 a time when to initiate a reception of the beam sweep transmission based at least partially on the obtained information and the acquired configuration information, thereby allowing said wireless communication device to enter, or remain in, a first activity state until the determined time. The method also comprises entering S4, at the determined time, a second activity state whereby said wireless communication device is capable to receive the beam sweep. There is also disclosed a complementary method performed by a radio network node as well as corresponding devices and computer programs.

TECHNICAL FIELD

The proposed technology generally relates to methods and devices thatenables reception beam sweep transmissions. In particular it relates tomethods and devices that enable a wireless communication device toutilize an energy saving mode of operation while at the same timeensuring a reliable reception of beam sweep transmissions.

BACKGROUND

The spectrum for 5G/NX systems is generally expected to be allocated inhigher frequency bands than the spectrum for today's cellular systems,even in the millimeter wave region. At these high frequencies, thepropagation conditions, in terms of attenuation, penetration andrefraction, are not as favorable for wireless communications as thelower frequencies utilized today. To overcome these problems, 5G/NXsystems are assumed to rely heavily on beamforming in order to moreefficiently direct the radiated energy towards the intended receiver.This has the great advantage that the coverage area can be increased,but it is also associated with problems, since the reliance onbeamforming prevents an access node from reaching its entire intendedcoverage area, unless access nodes are deployed densely enough tocompensate for the poor propagation conditions.

Because of the above circumstances, an access node transmitting a signalmay transmit the signal using a single omnidirectional transmission,transmit it using a few consecutive wide beams, which together coveringthe entire coverage area, or using a potentially great number ofconsecutive narrow beams. In the general case, multiple consecutivelytransmitted narrow beams can be assumed to be used, this is referred toas a beam sweep.

Discontinuous Reception, DRX, is a possible way to enable a wirelesscommunication device to save energy by staying in a low-power sleep modemost of the time and only wake up to receive certain signals, such assignals carrying tracking area information, monitor paging occasions andperform measurements.

Having as short awake periods as possible is crucial to make the DRXefficient and the energy consumption low. In the context of e.g.reception of tracking area information, short awake periods can beachieved if the occasions when the signal is transmitted are welldefined. However, in the case where this information is transmittedusing beam sweeps, the time to receive the signal is inherently vaguelydefined, because it is unknown which of the beams in the beam sweep thewireless communication device will be able to receive. The result isthat the signal transmission/reception occasion is extended to a longertime window that covers the entire beam sweep duration. Hence, becauseof the need for beam sweeping, the awake time periods when using DRXbecome much longer than required for reception of a single transmission.This can potentially severely degrade the performance of the DRX andsignificantly increase the energy consumption, which is especiallyunfavorable for energy deprived devices, such as many MTC devices, e.g.sensor devices.

The proposed technology aims to provide counter measures to theinterconnected problems of beam sweep transmissions and energydeprivation of potentially receiving devices. It aims in particular toprovide mechanisms whereby a wireless communication device can saveenergy, or power, and at the same time receive information transmittedto the device using beam sweep transmissions.

SUMMARY

It is an object to provide methods and devices that enables a wirelesscommunication device to receive information transmitted during a beamsweep transmission. Another object is to provide methods and devicesthat enable a wireless communication device to perform an energyefficient reception of information transmitted using beam sweeptransmissions.

According to a first aspect, there is provided a method performed by awireless communication device to enable the reception of a beam sweeptransmission. The method comprises obtaining information enabling thewireless communication device to determine whether it is stationary, oressentially stationary. The method also comprises acquiringconfiguration information comprising information about the starting timefor the beam sweep transmission. The method also comprises determining atime, when to initiate a reception of the beam sweep transmission basedat least partially on the obtained information and the acquiredconfiguration information, thereby allowing the wireless communicationdevice to enter or remain in a first activity state until the determinedtime. The method also comprises entering, at the determined time, asecond activity state whereby the wireless communication device iscapable to receive the beam sweep.

According to a second aspect there is provided a transmission methodperformed by a radio network node to enable a wireless communicationdevice to receive information transmitted from the radio network node ina beam sweep transmission, wherein the wireless device is in at leastone of an idle state, a dormant state, an energy saving state and anon-receiving state. The method comprises transmitting configurationinformation to the wireless communication device, the configurationinformation comprising at least the starting time for the beam sweeptransmission. The method also comprises transmitting information to bereceived by the wireless communication device in a beam sweeptransmission at the transmitted starting time.

According to a third aspect there is provided a wireless communicationdevice configured to receive information transmitted during a beam sweeptransmission. The wireless communication device is configured to obtaininformation enabling the wireless communication device to determinewhether it is stationary or essentially stationary. The wirelesscommunication device is also configured to acquire configurationinformation comprising information about the starting time for the beamsweep transmission. The wireless communication device is also configuredto determine a time to initiate a reception of the beam sweeptransmission based at least partially on the obtained information andthe acquired configuration information thereby allowing the wirelesscommunication device to enter or remain in a first activity state untilthe determined time. The wireless communication device is alsoconfigured to enter, at the determined time, a second activity statewhereby the wireless communication device is capable to receive the beamsweep.

According to a fourth aspect there is provided a radio network nodeconfigured to transmit configuration information enabling a wirelesscommunication device to receive information transmitted from the radionetwork node in a beam sweep transmission, wherein the wireless deviceis in at least one of an idle state, a dormant state, an energy savingstate and a non-receiving state. The radio network node is configured totransmit configuration information to the wireless communication device,the configuration information comprising at least the starting time forthe beam sweep transmission. The radio network node is also configuredtransmit information to be received by the wireless communication devicein a beam sweep transmission at the transmitted starting time.

According to a fifth aspect there is provided a computer program which,when executed by at least one processor, controls the reception of abeam sweep transmission, wherein the computer program comprisesinstructions that cause the at least one processor to:

read information for determining whether a wireless communication deviceis stationary, or essentially stationary

read configuration information comprising information about the startingtime for a beam sweep transmission

determining a time to initiate a reception of the beam sweeptransmission based at least partially on the information for determiningwhether a wireless communication device is stationary, or essentiallystationary, and the acquired configuration information, and

initiate a reception of the beam sweep transmission at the determinedtime.

According to a sixth aspect there is provided an apparatus forcontrolling a reception of a beam sweep transmission. The apparatuscomprises a reading module for reading information for determiningwhether a wireless communication device is stationary, or essentiallystationary. The apparatus also comprises a reading module for readingconfiguration information comprising information about the starting timefor the beam sweep transmission. The apparatus also comprises aprocessing module for determining a time to initiate a reception of thebeam sweep transmission based at least partially on the information fordetermining whether a wireless communication device is stationary, oressentially stationary, and the acquired configuration information. Theapparatus also comprises an initiation module for initiating a receptionof the beam sweep transmission at the determined time.

Embodiments of the proposed technology make it possible to have a secureand reliable mode of operation for receiving information transmitted ina beam sweep transmission. At the same time the proposed technologyprovides mechanisms that enable a wireless communication device to saveenergy during times when no reception is expected. The proposedtechnology reduces the number of beam transmission periods that a moreor less stationary wireless communication device need to monitor frommany tens down to a single one. The proposed technology allows inparticular that the expected large portion of 5G/NX devices that will bestationary to reduce the time to stay awake for reception of e.g.location/area related signal such as Tracking Area Code, TAC, in LongTerm Evolution system, thereby improving the efficiency of the DRX modeand substantially improving the energy efficiency of the wirelesscommunication device. Saving energy in devices that are essentiallystationary is a particularly beneficial application, sinceenergy-deprived MTC devices, e.g. sensor devices, are expected torepresent a very large part of the stationary 5G/NX UEs.

Other advantages will be appreciated when reading the detaileddescription.

BRIEF DESCRIPTION OF THE DRAWINGS

The embodiments, together with further objects and advantages thereof,may best be understood by making reference to the following descriptiontaken together with the accompanying drawings, in which:

FIG. 1 is a schematic flow diagram illustrating a particular methodperformed by a wireless communication device according to the proposedtechnology.

FIG. 2 is a schematic flow diagram illustrating a particular methodperformed by a radio network node according to the proposed technology.

FIG. 3 is a block diagram illustrating a processor-memory implementationof a wireless communication device according to the proposed technology.

FIG. 4 is a block diagram illustrating a processor-memory implementationof a wireless communication device or a radio network node according tothe proposed technology, the block diagram also illustrates acorresponding communication circuit.

FIG. 5 is a computer program implementation of an embodiment of theproposed technology.

FIG. 6 is a diagram illustrating an apparatus comprising functionmodules according to the proposed technology.

FIG. 7 is a signaling diagram illustrating the cooperation between awireless communication device and a radio network node according to aparticular embodiment of the proposed technology.

DETAILED DESCRIPTION

Throughout the drawings, the same reference designations are used forsimilar or corresponding elements.

For a better understanding of the proposed technology, it may be usefulto begin with a brief system overview and an analysis of the technicalproblem.

In 5G wireless communication networks, the carrier frequencies areexpected to be very high. At these high carrier frequencies significantpropagation losses will occur. The free-propagation losses will increasedue to e.g., scattering, penetration and refraction. A particular way tocounter the problem of propagation losses is to use beamforming. Inbeamforming a signal is transmitted in a particular direction, in orderto increase the received signal energy at the receiving device. Intransmissions using beamforming a wireless device generates signals tobe transmitted in different directions, i.e. beam directions. Thetransmitting device transmit these signals in a number of possible beamdirections, the particular number depends on the capacity of the device.A transmitting device may in particular transmit signals usingomnidirectional transmission, a short sweep of wide beams or a longsweep of narrow beams, or anything in between, depending on thedeployment/coverage scenario. The receiving device aims to detect thetransmitted signals. Since the receiving device does not know theexplicit time when to receive signals transmitted by means of beamsweeping, since it is unknown which of the beams in the beam sweep thereceiving device is capable receive, the receiving device will need bein reception mode during a large part, or possible the entire duration,of the beam sweep window in order to be able to securely receive thetransmitted information. The result is that the wireless communicationdevice needs to be awake, i.e. in receiving mode, for time periods thatare much longer than the ones required for reception of a singletransmission. This will in turn negatively affect the receiving devicepotential to save energy by entering an energy saving mode or state. Ifan energy saving mode was entered during a beam sweep transmissionwindow there is a risk that relevant information was not received. Theproposed technology aims to provide mechanisms whereby a receivingdevice safely may enter, or remain in, an energy saving mode, e.g. anon-receiving mode or non-receiving state, while at the same time beingcertain that relevant information transmitted during the beam sweep issafely received. The method thus enables the wireless communicationdevice to enter or remain in an energy saving low activity state or modeduring most of the beam sweep, only to wake up or entering a higheractivity state or receiving mode when the time approaches for receptionof the signal in the beam sweep, whereupon it may then go back to thelower activity state again after reception of the signal.

A particular mechanism that ensures that the mentioned features can beobtained is provided by a method according to the proposed technology.FIG. 1 is a schematic flow diagram illustrating an example of themethod. It is in particular disclosed a method performed by a wirelesscommunication device 100 to enable the reception of a beam sweeptransmission. A beam sweep is a series of multiple consecutivelytransmitted narrow beams transmitted in slightly different directions tospan the entire intended coverage area. A beam sweep transmission is thetransmission of an information signal using a beam sweep in which thewireless device is receiving the signal through one or several of thebeams in the beam sweep. The method performed by a wirelesscommunication device 100 to enable the reception of a beam sweeptransmission comprises obtaining S1 information enabling the wirelesscommunication device 100 to determine whether it is stationary, oressentially stationary. The method also comprises acquiring S2configuration information comprising information about the starting timefor the beam sweep transmission. The method also comprises determiningS3 a time when to initiate a reception of the beam sweep transmissionbased at least partially on the obtained information and the acquiredconfiguration information, thereby allowing the wireless communicationdevice to enter, or remain in, a first activity state until thedetermined time. The method also comprises entering S4, at thedetermined time, a second activity state whereby the wirelesscommunication device is capable to receive the beam sweep. The wirelessdevice thus switches from the first activity state to the secondactivity state at the determined time. The method may further comprisereturning S5, after reception of the transmitted beam sweep, i.e. afterreception of the signal transmitted in the beam sweep, to the firstactivity state.

The proposed method provides a mechanism whereby a wirelesscommunication device is able to determine a time when to initiatereception of a beam sweep transmission. The fact that such a time can bedetermined makes it possible for the wireless device to switch betweendifferent activity states. This will in turn ensure that the device maygo to sleep, i.e. entering a low energy consuming state, during timeperiods when no reception is expected. At the determined time the devicemay wake up and enter a second activity state in which the device iscapable to receive the beam sweep transmission, and then after receptionreturn to or reenter the first lower energy consuming activity state.The proposed technology therefore enables a highly energy savingoperation.

The time to initiate the reception is determined based on at leastconfiguration information comprising the starting time for the beamsweep transmission and information whether the wireless communicationdevice is stationary, or subject to minor movements, i.e. essentiallystationary. The configuration information and the information allowingthe wireless communication device to determine whether it is stationary,or essentially stationary, can be obtained by the device in any order.The configuration information could, according to particular embodimentsof the method, be acquired S2 or obtained from information transmittedfrom either the beam sweep transmitting node or some other node in thenetwork that may control or monitor the scheduling of the beam sweeptransmissions within the network. The wireless communication device mayalso be pre-configured with the configuration information, whereby thedevice can acquire it from its configuration settings, this may forexample be the case when periodic beam sweep transmissions areperformed, successive beam sweep transmissions beginning atapproximately the same time and using approximately the same beam sweepdirections.

The information allowing the wireless communication device to determinewhether it is stationary, or essentially stationary, can be obtained S1in numerous ways to be described later. There will in particular bedescribed certain embodiments that illustrates how the method maycollect and utilize information about earlier received beam sweeptransmissions in order to determine whether it is stationary or not.

The proposed method also comprises the step S3 of determining a timewhen to initiate a reception of the beam sweep transmission. The methodmay in certain embodiments begin by determining whether it isstationary, or nearly stationary. If it is the case that the wirelesscommunication is essentially or nearly stationary the method may proceedand either determine S3 the time by using the starting time as acquiredwith the configuration information or some time offset from the acquiredstarting time. If the wireless device is not determined to be stationaryor essentially stationary, the time is determined S3 to be the acquiredstarting time of the beam sweep transmission. Certain examples of thiswill be described in later section. Having determined S3 a receptiontime, the wireless communication device may enter or remain in a firstactivity state until it is time to initiate a reception by entering asecond activity state where reception is enabled. The first activitystate may preferably be a low energy consuming state, such as an idlestate or mode, a dormant state or mode or a non-receiving state or mode.The second activity state is typically a higher energy consuming statethan the first state, a receiving state in which reception of the signaltransmitted in the beam sweep is possible.

A particular embodiment of the proposed technology therefore provides amethod, wherein the first activity state is at least one of an idlestate, a dormant state, an energy saving state and a non-receiving stateand wherein the second activity state is a receiving state. According tothis embodiment a wireless communication device determines S3 a timewhen to initiate a reception of the beam sweep transmission. This couldoptionally be done when the wireless communication device is in areceiving state, or equivalently when in receiving mode, it may howeveralso be in a non-receiving state. After having determined the particulartime, by utilizing the obtained information about the stationarity ofthe device, and the acquired configuration information, such as thestarting time of the beam sweep transmission, the wireless communicationdevice may enter or remain in a first activity state that has a reducedenergy consumption. The device may remain in this energy saving state ormode until the time for initiating a reception approaches. At this timethe wireless communication device enters a second activity state wherereception of beam sweep transmissions is enabled. After reception of thebeam sweep transmission the wireless communication device could returnto the first activity state, and could remain in this state until a newtime for a second or further beam sweep, periodic or non-periodic, isdetermined. This embodiment provides a particularly efficient way toreduce the energy consumption of the wireless communication device byswitching between a lower and a higher energy consumption state, whileat the same time ensuring that information is securely received.

Another particular embodiment of the proposed technology provides amethod that comprises acquiring S2 configuration information byreceiving a message comprising the configuration information. Themessage could, for example, be sent by means of a signal transmitted atsome lower frequency than the frequency used for the beam sweeptransmission. By way of example, the acquired configuration informationcould be received in a message transmitted from the radio network nodetransmitting the beam sweep transmission. The configuration informationcould comprise information about the starting time for the beam sweeptransmission. The configuration information could also includeinformation about the sequence of beams used in the beam sweep, or otherinformation helping the wireless communication device to determine atime when a beam in the beam sweep transmission will reach the device,i.e. a time when the device will be able to receive the signal andinformation transmitted in the beam sweep transmission.

Still another embodiment of the proposed technology relates to a methodwherein the step of determining S3 a time to initiate a reception of thebeam sweep transmission is performed differently if the wirelesscommunication device has been determined to be stationary, oressentially stationary compared to non-stationary or mobile. If thewireless device is not determined to be stationary or essentiallystationary, the time will be determined S3 to be the starting time ofthe beam sweep transmission as acquired in the configurationinformation. If the device is determined S1 to be stationary oressentially stationary, then the time will be determined S3 to either bethe starting time of the beam sweep transmission as acquired in theconfiguration information, e.g. when the wireless communication deviceis reached by one of the first beams in the beam sweep transmission, ora later time occurring after the starting time of the beam sweeptransmission. The later time may then be determined S3 according toknowledge about the sequence of beams in the beam sweep transmission,knowledge about the position of the node and the wireless device itselfor other information allowing the wireless device to determine the timeat which a beam in the beam sweep transmission will reach the wirelesscommunication device, or by calculating a time offset between thereception time of a beam in an earlier beam sweep transmission from thesame network node and the starting time of the beam sweep transmission.The wireless communication device may determine S3 the time of receptionof a beam in a beam sweep transmission by monitoring the full beam sweeptransmission, registering or recording the reception time of the beam inthe beam sweep transmission and then calculating a time offset betweenthe beam sweep starting time and the beam reception time, anddetermining S3 the reception time based on the time offset. Optionallythe wireless device uses information already obtained regarding thetiming offset, e.g. from an earlier beam sweep transmission, and usesthe information to determine S3 a starting time for reception of a beamsweep transmission.

The method also comprises entering S4, at the determined time, a secondactivity state whereby the wireless communication device is capable toreceive the beam sweep. The wireless communication device may enter thesecond activity state at the determined time, or slightly before. Forexample, a guard period or similar might be entered before thedetermined time for reception of a beam in the beam sweep, and thewireless communication device might enter the second activity state atthe beginning of the guard period. The duration of the guard periodcould for example be set to be a fraction of the transmission window fora particular direction of a beam in the beam sweep. The specific lengthof the guard interval may for example be set to 1/20 to ⅓ of thetransmission window for a particular direction.

The proposed technology also provides an embodiment wherein the methodfurther comprises determining S3 a time to initiate a reception of thebeam sweep transmission further comprises registering the time ofreception of the information transmitted during the beam sweeptransmission. This could preferably be done if the wirelesscommunication device has been determined to be stationary, oressentially stationary. That is, the particular time of reception when awireless communication device actually received the informationtransmitted during the beam sweep transmission is registered. Theregistered time of reception may be used in different embodiment tofurther improve the proposed technology.

According to a possible embodiment of the proposed technology there isprovided a method wherein the step of determining S3 a time to initiatea reception of the beam sweep transmission is based on the time ofreception of information transmitted during an earlier beam sweeptransmission. That is, knowledge about the reception time of earlierreceived beam sweep transmission is used as the time when to initiate areception by entering S4 the second activity state.

In one such embodiment the registered time is used in order to find thedifference between the actual reception time and the acquired time, thiscan be used to improve the step of determining a time in which receptionis initiated by entering a second activity state. To this end theembodiment provides a method wherein the step of determining alsocomprises comparing the registered time of reception with the acquiredstarting time for the beam sweep transmission in order to obtain ameasure of the time offset between the reception time and the acquiredstarting time.

Another embodiment that utilizes the registered time relates to a methodwherein a time for initiating a reception of a subsequent beam sweeptransmission is determined based at least partially on the measure ofthe time offset between the reception time and the acquired startingtime of an earlier received beam sweep transmission.

As a highly simplified example, one may consider the case where wirelesscommunication device in step S3 determines that the time to initiate thereception coincides with starting time acquired by means of theconfiguration information. If the reception mode or reception state,i.e. the second activity state, is entered at the determined time and ifthe actual reception time, as registered, occurred at a later time, theparticular offset between the times may be used to improve thedetermination of the time to initiate a reception. If for example theconfiguration information provides information that a particular beamsweep transmission will begin at time T0, and then be repeated at T1,T2, T3, etc., and if the registered receiving time yields informationthat the information was received at T0+t*, the time offset measure canbe determined to be t*. This can be used to improve the accuracy offuture reception time determinations. The next determined time forentering the second activity state may for example be set to T1+½t*.This scheme may be repeated several times in order to obtain better andbetter values for the determined time. Having performed the process anumber of times to obtain a number of time offset measures one mayprocess the time offsets statistically to obtain a reasonable measure touse for future receptions. A particular example would be to use the meanvalue of all the determined time offsets.

According to still another embodiment where the registered receptiontime is used provides a method, wherein the step of obtaining S1information comprises to obtain a measure of the time offset for atleast two different receptions to enable the wireless communicationdevice 100 to determine whether it is stationary based on a comparisonbetween the measures of the time offset.

That is, information that time offsets obtained during the differentreceptions differ may be used to determine whether the wirelesscommunication device is stationary or not. The fact that the timeoffsets more or less coincides provides as a clear indication that thewireless communication device is stationary, while substantiallydiffering time offsets provides ample indications that the device is infact not stationary. It should be noted that the communication devicecan be considered to be stationary as long as the relevant beam sweeptransmission is actually received. A wireless communication device maytherefore be allowed to move slightly as long as the time offsetcompensate for the slight motion.

Beside the use of time offsets to determine whether the wirelesscommunication device is stationary the proposed technology provides fora number of different possibilities to determine the stationarity of thedevice. The device is determined to be stationary or essentiallystationary by evaluating information obtained or available to thewireless device. The device will then receive the beam sweeptransmission, such as one or a few beams of the beam sweep, essentiallyat the same time in relation to the starting time of the beam sweep forconsecutive beam sweeps.

There is in particular provided a method, wherein the step of obtainingS1 information comprises to obtain information in the form of one ormore of the following:

-   -   information about the output from a sensor device providing        information about the position of the wireless device to enable        the wireless communication device 100 to determine that is        stationary by checking that the output is essentially constant,    -   information related to hand-overs of the wireless communication        device 100 to enable the wireless communication device 100 to        determine that it is stationary by checking whether it has        subjected to a handover during a predetermined time period,    -   information relating to estimations of certain channel        properties, such as dispersion or delay profile, to enable the        wireless communication device 100 to determine that it is        stationary by checking if these channel properties have remain        constant during a predetermined time period,    -   information relating to estimations of a Doppler spread to        enable the wireless communication device 100 to determined that        it is stationary by checking whether the estimations indicate a        Doppler spread that is essentially zero,    -   information about the geographical position of the wireless        communication device 100 provided by a UE-internal GPS receiver        to enable the wireless communication device 100 to determine        whether it is stationary by checking if the information provides        indications that the geographical position have remained        constant during a predetermined time period.

All the above listed information sources may advantageously be combinedin basically any combination. Which information sources to use and thedegree of certainty that is required is up to the particularimplementation.

The method according to the proposed technology can suitable be used forthe case where the information received in the beam sweep transmissioncomprises system information, paging information or other informationthat the wireless communication device needs to monitor when in thefirst activity state.

According to a particularly useful embodiment of the proposed there isprovided a method wherein the information received during the beam sweeptransmission comprises tracking area information instructing thewireless communication device 100 to perform a tracking area update.

The proposed technology also provides an embodiment of the method,wherein the acquired configuration information also comprisesinformation about the sequence of beams used in the beam sweeptransmission.

According to yet another embodiment of the proposed technology there isprovided a method wherein the beam sweep transmission is a periodic beamsweep transmission. This particular embodiment of the proposedtechnology addresses deployments where the transmitting radio networknode performs periodic beam sweep transmissions at apredetermined/preconfigured time and using the same sequence of beams.That is, different transmit directions are always covered in the sameorder in the sweep. Such examples are when the node is transmittingsystem information, paging information, tracking area information or anyother information that the wireless communication device needs tomonitor even when it is in a low energy or non-receiving state. Thiskind of information is typically transmitted with a certain periodicityand with a similar or identical beam sweep. The wireless communicationdevice might thus obtain a periodic series of starting times for beamsweep transmissions of such information and using the method of theinvention be able to determine a time to receive the transmissions basedon a previously known or determined time offset. The wirelesscommunication device may thus be able to wake up or enter a higheractivity state for a shorter period of time than it would if it were tomonitor the whole beam sweep transmission window, and is thus able todecrease its energy consumption.

A particularly useful embodiment when the beam sweep transmission is aperiodic beam sweep transmission is provided by a method wherein theacquired configuration information further comprises the periodicity ofsaid periodic beam sweep transmission. The information may be acquiredin several ways, the wireless communication device may have received theinformation in a message transmitted from the beam sweep transmittingnode, or some other transmission controlling node within the network.The device may also been provided with control information enabling thedevice control its setting to account for the periodicity. An example ofa particular use of an embodiment where information about theperiodicity is used relates to a case where the reception time of a beamsweep transmission is determined S3 to be t+T, where t refers to theregistered time of reception for an earlier beam sweep, and T refers tothe period of the periodic beam sweep transmission. A reception of thebeam sweep transmission may thus be initiated at t+T by entering S4 thesecond activity state. This embodiment may also be altered to take timeoffsets and guard interval, as described earlier, into account.

In case of a periodic beam sweep transmission, the proposed technologyalso provides a possible embodiment of a method wherein the methodcomprises determining S3 a sequence of times when to initiate receptionof beam sweep transmissions based on the obtained information and theacquired configuration information and on the periodicity of the beamsweep transmissions. That is, if a periodic beam sweep transmission isused, the method may proceed and determine a sequence of times when toinitiate a reception by entering a second activity state where thewireless communication device is capable of receiving the beam sweeptransmission. The method may in particular determine a first time bymeans of the obtained and acquired information and having determined thefirst time a sequence of times may be obtained since the starting timesfor the beam transmissions follows a repetitive pattern. Hence asequence of times may be obtained by knowing the period between twosuccessive transmissions and optionally a potential time offset. More ofthis will be described later.

The embodiment where a sequence of times are determined provides for away whereby a wireless communication device is allowed to automaticallyswift between a first activity state with e.g. a low energy consumptionand a second activity state where the wireless communication device iscapable of receiving the beam sweep transmission. As a concrete butnon-limiting example the wireless communication device may initially bein the second activity state, or at least in a state allowing reception.Since the wireless communication device is capable of receivinginformation when in the second state, the wireless communication deviceis allowed to acquire configuration information transmitted from e.g.the beam sweep transmitting node. The wireless communication device mayuse this information together with knowledge that it is essentiallystationary in order to determine a first time when to initiate receptionby shifting activity states. The knowledge of this particular timetogether with knowledge about the periodicity of the beam sweeptransmission will enable the device to determine a number of times whento initiate a reception of the beam sweep transmission. Havingdetermined a particular sequence the wireless communication device mayenter a first activity state, e.g. a low energy consuming state such asa non-receiving state. When the first determined time approaches thewireless communication device initiates a reception by entering thesecond activity state where reception is enabled. The device receivesand may decode the information, and if the content of the same allowsit, the device may return to the first activity state and remain thereuntil the next determined time in the sequence approaches. This processmay continue until configurations regarding either the beam sweeptransmissions or the stationarity of the device is altered.

To illustrate this consider the case with a Long Term Evolution network,LTE network. In LTE, tracking is a functionality which supports locatingwireless devices, e.g. User Equipments, UEs, within the network. Thenetwork is broken down into Tracking Areas, TAs. The network configuresa UE in idle mode, a particular low activity mode, with one or moretracking areas. This allows the network to locate the UE within acertain defined region. When the UE enters a tracking area which is notin the list provided by the network, the UE performs a tracking areaupdate. This update assists the network to update the UE locationinformation, which enables the network to contact the UE through pagingwhen needed.

The method to indicate the tracking area is via system information. InLTE, the Tracking Area Code, TAC, is contained in System InformationBlock Type 1, SIB1, which is periodically transmitted in each cell.

A UE in idle mode has to monitor the TAC, i.e. SIB1, in order to detectwhen a tracking area update is needed. Tracking are information such asTAC will certainly be relevant also in 5G network, and the proposedtechnology is ideally suited to handle the transmission and reception ofthis type of information using beam sweep transmissions.

We will now provide a few examples of how the proposed technology may beused in certain applications. The provided examples are merely intendedto illuminate certain aspects of the proposed technology and should notbe considered as limitations.

In a first example the proposed technology targets the subset of thewireless communication devices that are stationary. Since a largeportion of the envisioned 5G/NX devices are expected to be stationary,e.g. mass-deployed sensor devices, a mechanism targeting this subsetwould be highly beneficial. Furthermore, energy conservation is ofparticular importance in such devices, due to e.g. the limited batterypower of a sensor. The first example also targets the scenario where thebeam sweep transmission transmits tracking area information via atracking area signal, referred to below as a TRAS.

An access node transmitting a TRAS by means of a beam sweep transmissionmay transmit it using omnidirectional transmission, a short sweep ofwide beams or a long sweep of narrow beams, or anything in betweenreally, depending on the deployment/coverage scenario. The proposedtechnology may address deployments where the access node always begins aperiodic TRAS transmissions, e.g. an omnidirectional transmission witheither a short sweep or a long sweep, at a predetermined/preconfiguredtime and always uses the same sequence of beams. That is, differentdirections are always covered in the same order, in the sweep. Awireless communication device, such as a UE in Dormant mode may beconfigured with knowledge of this periodic transmission start time, aswell as the maximum beam sweep time.

A particular feature of the proposed technology is that a stationary UEmay obtain knowledge of its stationary property, through any of thenumber of possible mechanisms described earlier, and may record the timeoffset after the configured TRAS transmission start time that itreceives the TRAS. Based on such detection, or several repeatedmeasurements indicating substantially the same time of reception inrelation to the configured transmission start time, the UE learns whenit can expect to receive the periodic TRAS and may delay its wakeup timeaccordingly.

The proposed technology may utilize the stationary property of the UE,i.e. the lack of physical movement of the device during an extendedperiod, and relies on the UE to obtain knowledge about this property. Inaddition, according to a particular example, a UE in Dormant state isconfigured with the start time of a window, and also possibly the lengthof the window, for TRAS reception rather than a single occasion forreception of a single TRAS transmission. As discussed, depending ondeployment, that is the coverage scenarios, the TRAS may be transmittedin an omnidirectional fashion, using a sweep of wide beams or using asweep of narrow beams. According to the particular example with periodicbeam sweeps, the transmitting access node should always start the beamsweep, or the omnidirectional transmission, at the same preconfiguredtime, i.e. at a time instant corresponding to a multiple of TRAStransmission period, plus an optional fixed offset, according to thesystem clock.

Under the assumption that the UE is configured with the same time, theUE does not have to know beforehand whether it will be covered byomnidirectional transmission, a sweep of wide beams or a sweep of narrowbeams, but a consequence is that the UE has to be prepared to receivethe TRAS not only at a specific occasion but during a time windowstarting at the preconfigured time, possibly with some margin to accountfor clock drift, and ending after a time period corresponding to thelongest possible beam sweep. However, as soon as the UE receives theTRAS it may go back to sleep. According to the proposed technology it isalso possible that the access node, i.e. the radio network nodeperforming the beam sweep transmission, always uses the same sequence ofbeams in its TRAS beam sweep transmission. That is, different directionswill always be covered in the same order. In such a particular case a UEknowing that it is stationary may use the knowledge to optimize itsreception, i.e. optimizing the time period when to be in a receivingstate. As a consequence the UE may also increase its sleep time, i.e.increase the time when in an energy saving non-receiving mode or state.

The stationary UE can notice that it always receives the TRAS a certaintime after the beginning of the TRAS observation window, whichcorresponds to a certain beam direction in the sweep. When this islearnt, the UE can adapt its wakeup time accordingly and thus reduce thetime it has to stay awake just to wait for the TRAS. Using thisprinciple/mechanism the UE can potentially reduce the time it staysawake to a small fraction, thereby improving the efficiency of the DRXand saving substantial amounts of energy.

The configuration of the UE in terms of TRAS transmission period andtime window, or the start of time window, for TRAS transmission could bedone when the UE is switched to dormant mode, i.e. a low activity mode.Alternatively the UE could be configured immediately after or inconjunction with establishment of a RRC connection, i.e. when the UEenters active mode, or at any time while the UE is in active mode. Yetanother alternative may be that the UE receives this configurationinformation through the system information.

The proposed method has been described using the example of a physicallystatic wireless communication device. This wireless communication devicemay e.g. be a sensor device at a fixed location. The principle of theinvention may also be applied to wireless communication devices that aretemporarily static, e.g. a smartphone placed on a table. Once thewireless communication device is moved after a static phase, it maydetect the movement e.g. since the TRAS is detected at a later timeinstant, or the TRAS is not detected when the UE is waking up just intime according to the previously optimal beam timing. Alternatively,change in any of the other criteria above may be used as an indicationthat the assumption that the wireless communication device is stationaryno longer holds. In such a case, the wireless communication device mayreturn to the standard TRAS reception behavior, attempting TRASdetection during the entire observation window.

Having described a method performed by a wireless communication deviceto enable the wireless communication device to perform reception of abeam sweep transmission we will now describe a complementary methodperformed by a radio network node. It should be noted that a radionetwork node according to the present application may be an access node.

The complementary method performed by the radio network node isparticularly relevant in an embodiment where the radio network nodeinforms the wireless communication device about the details of anupcoming beam sweep transmission. That is, the radio network nodeprovides the wireless communication device with configurationinformation that the wireless communication device can use to at leastpartially determine a time when to initiate a reception by entering anactivity state in which it is capable to receive the beam sweeptransmission. A signaling diagram illustrating the cooperation isprovided by FIG. 7.

The method performed by the radio network node is illustrated in FIG. 2.In more detail it is illustrated a method performed by a radio networknode 200 for enabling a wireless communication device 100 to receiveinformation transmitted from the radio network node 200 in a beam sweeptransmission, the wireless communication device 100 being in at leastone of a an idle state, a dormant state, an energy saving state and anon-receiving state. The method comprises transmitting S10 configurationinformation to the wireless communication device, the configurationinformation comprising at least the starting time for the beam sweeptransmission. The method also comprises transmitting S20 information tobe received by the wireless communication device 100 in a beam sweeptransmission at the transmitted starting time.

The beam sweep transmission is, according to a particular embodiment ofthe method, a periodic beam sweep transmission.

According to another possible embodiment of the proposed technologythere is provided a method wherein the transmitted S10 configurationinformation also comprises information about the sequence of beams to beused in the beam sweep transmission and wherein the transmitted S20information to be received by the wireless device is transmitted in aperiodic beam sweep transmission with the sequence of beams.

The complementary aspects of the methods performed by the wirelesscommunication device and the radio network node provides a particularlyefficient way to ensure safe reception of information while display thebeneficial bonus of allowing a wireless communication device to saveenergy.

Having described various embodiments of the methods according to theproposed technology, in the following there will be described specificdevices apparatuses and computer programs suitable to implement thedifferent methods. All advantages associated to the methods translatesto the devices, apparatuses and computer programs and will not berepeated.

According to the proposed technology there is provided a wirelesscommunication device 100 configured to receive information transmittedduring a beam sweep transmission. The wireless communication device 100is configured to obtain information enabling the wireless communicationdevice 100 to determine whether it is stationary, or essentiallystationary. The wireless communication device 100 is also configured toacquire configuration information comprising information about thestarting time for the beam sweep transmission. The wirelesscommunication device 100 is also configured to determine a time toinitiate a reception of the beam sweep transmission based at leastpartially on the obtained information and the acquired configurationinformation thereby allowing the wireless communication device to enter,or remain in, a first activity state until the determined time. Thewireless communication device 100 is also configured to enter, at thedetermined time, a second activity state whereby the wirelesscommunication device is capable to receive the beam sweep. The wirelesscommunication device may optionally also be configured to return to thefirst activity state, after reception of the beam sweep, and couldremain in the first activity state until a new time for a second orfurther periodic beam sweep is determined.

By way of example, in a possible embodiment of the wirelesscommunication device, is the first activity state at least one of anidle state, a dormant state, an energy saving state and a non-receivingstate and the second activity state is a receiving state. The firstactivity state is typically a lower activity state consuming less energythan the second activity state that is typically a higher activity stateconsuming more energy.

Another possible embodiment provides a wireless communication device 100that is configured to acquire configuration information by receiving amessage comprising the configuration information.

An efficient embodiment of the proposed technology provides a wirelesscommunication device 100 that is configured to acquire the configurationinformation in a message transmitted from the radio network node 200transmitting the beam sweep transmission.

Still another embodiment of a wireless communication device provides awireless communication device that is configured to determine a time toinitiate a reception of the beam sweep transmission if the wirelesscommunication device has been determined to be stationary, oressentially stationary.

A possible embodiment of a wireless communication device according tothe proposed technology relates to a wireless communication device 100that is configured to determine a time to initiate a reception of thebeam sweep transmission based on the time of reception of informationtransmitted during an earlier beam sweep transmission.

An advantageous embodiment of the proposed technology provides awireless communication device 100 that is further configured to registerthe time of reception of the information transmitted during the beamsweep transmission if the wireless communication device has beendetermined to be stationary, or essentially stationary A particularversion of the advantageous embodiment of the proposed technologyprovides a wireless communication device 100 that is further configuredto compare the registered time of reception with the acquired startingtime for the beam sweep transmission in order to obtain a measure of thetime offset between the reception time and the acquired starting time.

Another particular version of the advantageous embodiment of theproposed technology provides a wireless communication device 100 that isfurther configured to determine a time for initiating a reception of asubsequent beam sweep transmission based at least partially on the timeoffset between the reception time and the acquired starting time of anearlier received beam sweep transmission.

Yet another particular version of the advantageous embodiment of theproposed technology provides a wireless communication device 100 that isconfigured to obtain information by obtaining a measure of the timeoffset for at least two different receptions to enable the wirelesscommunication device 100 to determine whether it is stationary based ona comparison between the measures of the time offset.

A particular embodiment of the proposed technology provides a wirelesscommunication device 100 that is configured to obtain information in theform of one or more of the following:

-   -   information about the output from a sensor device providing        information about the position of the wireless device to enable        the wireless communication device 100 to determine that it is        stationary by checking that the output is essentially constant;    -   information related to hand-overs of the wireless communication        device 100 to enable the wireless communication device 100 to        determine that it is stationary by checking whether it has        subjected to a handover during a predetermined time period;    -   information relating to estimations of certain channel        properties, such as dispersion or delay profile, to enable the        wireless communication device 100 to determine that it is        stationary by checking if these channel properties have remain        constant during a predetermined time period;    -   information relating to estimations of a Doppler spread to        enable the wireless communication device 100 to determined that        it is stationary by checking whether the estimations indicate a        Doppler spread that is essentially zero;    -   information about the geographical position of the wireless        communication device 100 provided by a UE-internal GPS receiver        to enable the wireless communication device 100 to determine        whether it is stationary by checking if the information provides        indications that the geographical position have remained        constant during a predetermined time period.

A particular embodiment of the proposed technology provides a wirelesscommunication device 100, wherein the information received in the beamsweep transmission comprises system information, paging or otherinformation that the wireless communication device needs to monitor whenin the first activity state.

A possible embodiment of the proposed technology provides a wirelesscommunication device 100 wherein the information transmitted during thebeam sweep transmission comprises tracking area information instructingthe wireless communication device 100 to perform a tracking area update.

Still another possible embodiment of the proposed technology provides awireless communication device 100 wherein the acquired configurationinformation also comprises information about the sequence of beams usedin the beam sweep transmission.

According to yet another embodiment of the proposed technology there isprovided a wireless communication 100, wherein the beam sweeptransmission is a periodic beam sweep transmission.

A related embodiment relates to a wireless communication device that isconfigured to acquire configuration information that comprises theperiodicity of said periodic beam sweep transmission.

A possible embodiment of the proposed technology provides a wirelesscommunication device 100 that is further configured to determine asequence of times when to initiate a reception based on the obtainedinformation and the acquired information and on the periodicity of thebeam sweep transmission.

FIG. 3 provides a block diagram illustrating a particular version of awireless communication device 100 according to the proposed technology.The wireless communication device 100 comprises a processor 120 andmemory 130, the memory 130 comprising instructions executable by theprocessor 110, whereby the processor 120 is operative to control areception of information transmitted during a beam sweep transmission.

FIG. 4 discloses is a wireless communication device 100 that alsocomprises a communication circuitry 110. The device 100 may also includea communication circuit 110. The communication circuit 110 may includefunctions for wired and/or wireless communication with other devicesand/or network nodes in the network. In a particular example, thecommunication circuit 110 may be based on radio circuitry forcommunication with one or more other nodes, including transmittingand/or receiving information. The communication circuit 110 may beinterconnected to the processor 120 and/or memory 130. By way ofexample, the communication circuit 130 may include any of the following:a receiver, a transmitter, a transceiver, input/output (I/O) circuitry,input port(s) and/or output port(s).

It should be notes that, as used herein, the non-limiting terms“wireless communication device”, “station”, “User Equipment (UE)”, and“terminal” may refer to a mobile phone, a cellular phone, a PersonalDigital Assistant (FDA), equipped with radio communication capabilities,a smart phone, a laptop or Personal Computer (PC), equipped with aninternal or external mobile broadband modem, a tablet with radiocommunication capabilities, a target device, a device to device UE, amachine type UE or UE capable of machine to machine communication,Customer Premises Equipment (CPE), Laptop Embedded Equipment (LEE),Laptop Mounted Equipment (LME), USB dongle, a portable electronic radiocommunication device, a sensor device equipped with radio communicationcapabilities or the like. In particular, the term “wirelesscommunication device” should be interpreted as non-limiting termscomprising any type of wireless device communicating with a network nodein a wireless communication system and/or possibly communicatingdirectly with another wireless communication device. In other words, awireless communication device may be any device equipped with circuitryfor wireless communication according to any relevant standard forcommunication.

The proposed technology also provides a radio network node 200configured to transmit configuration information enabling a wirelesscommunication device 100 to receive information transmitted from theradio network node in a beam sweep transmission, wherein the wirelessdevice (100) is in at least one of an idle state, a dormant state, anenergy saving state and a non-receiving state. The radio network node200 is configured to transmit configuration information to the wirelesscommunication device 100, the configuration information comprising atleast the starting time for the beam sweep transmission. The radionetwork node 200 is also configured transmit information to be receivedby the wireless communication device 100 in a beam sweep transmission atthe transmitted starting time.

A particular embodiment of the radio network node 200 according to theproposed technology provides a radio network node wherein the beam sweeptransmission is a periodic beam sweep transmission.

Another possible embodiment of the proposed technology provides a radionetwork node 200 that is configured to transmit configurationinformation that also comprises information about the sequence of beamsto be used in the beam sweep transmission and wherein radio network nodeis further configured to transmit information to be received by thewireless communication device 100 in a periodic beam sweep transmissionwith the sequence of beams.

FIG. 4 provides a block diagram illustration of a radio network node 200according to the proposed technology. The radio network node 200comprises a communication circuit 210, a processor 220 and a memory 230,the memory 230 comprising instructions executable by the processor 110,whereby the processor 220 is operative to initiate a transmission ofconfiguration information enabling a wireless communication device 100to receive information transmitted during a beam sweep transmission. Aradio network node may also include a communication circuit 210. Thecommunication circuit 210 may include functions for wired and/orwireless communication with other devices and/or network nodes in thenetwork. In a particular example, the communication circuit 210 may bebased on radio circuitry for communication with one or more other nodes,including transmitting and/or receiving information. The communicationcircuit 210 may be interconnected to the processor 220 and/or memory230. By way of example, the communication circuit 210 may include any ofthe following: a receiver, a transmitter, a transceiver, input/output(I/O) circuitry, input port(s) and/or output port(s).

It will be appreciated that the methods and arrangements describedherein can be implemented, combined and re-arranged in a variety ofways. For example, embodiments may be implemented in hardware, or insoftware for execution by suitable processing circuitry, or acombination thereof.

The steps, functions, procedures, modules and/or blocks described hereinmay be implemented in hardware using any conventional technology, suchas discrete circuit or integrated circuit technology, including bothgeneral-purpose electronic circuitry and application-specific circuitry.

Alternatively, or as a complement, at least some of the steps,functions, procedures, modules and/or blocks described herein may beimplemented in software such as a computer program for execution bysuitable processing circuitry such as one or more processors orprocessing units.

Examples of processing circuitry includes, but is not limited to, one ormore microprocessors, one or more Digital Signal Processors (DSPs), oneor more Central Processing Units (CPUs), video acceleration hardware,and/or any suitable programmable logic circuitry such as one or moreField Programmable Gate Arrays (FPGAs), or one or more ProgrammableLogic Controllers (PLCs).

It should also be understood that it may be possible to re-use thegeneral processing capabilities of any conventional device or unit inwhich the proposed technology is implemented. It may also be possible tore-use existing software, e.g. by reprogramming of the existing softwareor by adding new software components.

It is also possible to provide a solution based on a combination ofhardware and software. The actual hardware-software partitioning can bedecided by a system designer based on a number of factors includingprocessing speed, cost of implementation and other requirements.

FIG. 5 is a schematic diagram illustrating an example of acomputer-implementation according to an embodiment. In this particularexample, at least some of the steps, functions, procedures, modulesand/or blocks described herein are implemented in a computer program135, which is loaded into the memory 130 for execution by processingcircuitry including one or more processors 120. The processor(s) 120 andmemory 130 are interconnected to each other to enable normal softwareexecution. An optional input/output device may also be interconnected tothe processor(s) 120 and/or the memory 130 to enable input and/or outputof relevant data such as input parameter(s) and/or resulting outputparameter(s).

The term ‘processor’ should be interpreted in a general sense as anysystem or device capable of executing program code or computer programinstructions to perform a particular processing, determining orcomputing task.

The processing circuitry including one or more processors 120 is thusconfigured to perform, when executing the computer program 135,well-defined processing tasks such as those described herein.

The processing circuitry does not have to be dedicated to only executethe above-described steps, functions, procedure and/or blocks, but mayalso execute other tasks.

According to a particular embodiment of the proposed technology there isprovided a computer program 135 which, when executed by at least oneprocessor 120, control the reception of a beam sweep transmission,wherein the computer program 135 comprises instructions that cause theat least one processor to:

read information for determining whether a wireless communication device100 is stationary, or essentially stationary

read configuration information comprising information about the startingtime for a beam sweep transmission

determining a time to initiate a reception of the beam sweeptransmission based at least partially on the information for determiningwhether a wireless communication device 100 is stationary, oressentially stationary, and the acquired configuration information; and

initiate a reception of the beam sweep transmission at the determinedtime.

The proposed technology also provides a computer-program productcomprising a computer-readable medium 145 having stored thereon acomputer program 135 as described above.

The proposed technology also provides a carrier comprising the computerprogram, wherein the carrier is one of an electronic signal, an opticalsignal, an electromagnetic signal, a magnetic signal, an electricsignal, a radio signal, a microwave signal, or a computer-readablestorage medium.

By way of example, the software or computer program 135 may be realizedas a computer program product, which is normally carried or stored on acomputer-readable medium, in particular a non-volatile medium. Thecomputer-readable medium may include one or more removable ornon-removable memory devices including, but not limited to a Read-OnlyMemory (ROM), a Random Access Memory (RAM), a Compact Disc (CD), aDigital Versatile Disc (DVD), a Blu-ray disc, a Universal Serial Bus(USB) memory, a Hard Disk Drive (HDD) storage device, a flash memory, amagnetic tape, or any other conventional memory device. The computerprogram may thus be loaded into the operating memory of a computer orequivalent processing device for execution by the processing circuitrythereof.

The flow diagram or diagrams presented herein may be regarded as acomputer flow diagram or diagrams, when performed by one or moreprocessors. A corresponding apparatus may be defined as a group offunction modules, where each step performed by the processor correspondsto a function module. In this case, the function modules are implementedas a computer program running on the processor.

The computer program residing in memory may thus be organized asappropriate function modules configured to perform, when executed by theprocessor, at least part of the steps and/or tasks described herein.

FIG. 6 is a schematic diagram illustrating an example of an apparatus300 for controlling a reception of a beam sweep transmission. Theapparatus 300 comprises a reading module 310 for reading information fordetermining whether a wireless communication device 100 is stationary,or essentially stationary. The apparatus 300 also comprises a readingmodule 310 for reading configuration information comprising informationabout the starting time for the beam sweep transmission. The apparatusalso comprises a processing module 320 for determining a time toinitiate a reception of the beam sweep transmission based at leastpartially on the information for determining whether a wirelesscommunication device 100 is stationary, or essentially stationary, andthe acquired configuration information. The apparatus also comprises aninitiation module 330 for initiating a reception of the beam sweeptransmission at the determined time.

Alternatively it is possible to realize the module(s) in FIG. 6predominantly by hardware modules, or alternatively by hardware, withsuitable interconnections between relevant modules. Particular examplesinclude one or more suitably configured digital signal processors andother known electronic circuits, e.g. discrete logic gatesinterconnected to perform a specialized function, and/or ApplicationSpecific Integrated Circuits (ASICs) as previously mentioned. Otherexamples of usable hardware include input/output (I/O) circuitry and/orcircuitry for receiving and/or sending signals. The extent of softwareversus hardware is purely implementation selection.

The embodiments described above are merely given as examples, and itshould be understood that the proposed technology is not limitedthereto. It will be understood by those skilled in the art that variousmodifications, combinations and changes may be made to the embodimentswithout departing from the present scope as defined by the appendedclaims. In particular, different part solutions in the differentembodiments can be combined in other configurations, where technicallypossible.

ABBREVIATIONS

-   -   3GPP 3rd Generation Partnership Project    -   5G 5th Generation    -   AIT Access Information Table    -   DRX Discontinuous Reception    -   eNB Evolved NodeB    -   EPS Evolved Packet System    -   GPS Global Positioning System    -   L3 Layer 3LTE Long Term Evolution    -   MTC Machine Type Communication    -   RAN Radio Access Network    -   RRC Radio Resource Control    -   SIB System Information Block    -   SSI System Signature Index    -   TA Tracking Area    -   TAC Tracking Area Code    -   TRAS Tracking RAN Area Signal    -   UE User Equipment

The invention claimed is:
 1. A method performed by a wirelesscommunication device to enable the reception of a beam sweeptransmission, wherein the method comprises: obtaining informationenabling the wireless communication device to determine whether it isstationary; acquiring configuration information comprising informationabout a starting time of the beam sweep transmission; determining a timeto initiate a reception of the beam sweep transmission based at leastpartially on the obtained information and the configuration information,thereby allowing the wireless communication device to enter, or remainin, a first activity state until the determined time; and entering, atthe determined time, a second activity state, whereby the wirelesscommunication device is prepared to receive the beam sweep transmission;wherein, when the obtained information indicates that the wirelesscommunication device is stationary, determining the time to initiate thereception of the beam sweep transmission comprises determining the timebased on a time offset determined from an earlier beam sweeptransmission, the time offset being between the starting time of theearlier beam sweep transmission and the reception by the wirelesscommunication device of a beam of the earlier beam sweep transmission.2. The method according to claim 1, wherein the first activity state isat least one of an idle state, a dormant state, an energy saving stateand a non-receiving state, and wherein the second activity state is areceiving state.
 3. The method according to claim 1, wherein acquiringthe configuration information comprises receiving a message comprisingthe configuration information.
 4. The method according to claim 3,wherein the message is transmitted from a radio network node thatperforms the beam sweep transmission.
 5. The method according to claim1, further comprising determining the time offset by comparing a time ofreception registered by the wireless communication device with respectto the beam received in the previous beam sweep transmission with thestarting time as indicated in the configuration information.
 6. Themethod according to claim 5, wherein obtaining the informationindicating whether the wireless communication device is stationarycomprises obtaining time offsets for at least two different beam sweeptransmissions and comparing the two different time offsets.
 7. Themethod according to claim 1, wherein the step of obtaining informationcomprises obtaining one or more of the following: information from asensor device about the position of the wireless communication devicethat enables the wireless communication device to determine that it isstationary, by checking the information from the sensor device;information related to handovers of the wireless communication devicethat enables the wireless communication device to determine that it isstationary, by checking whether it was subjected to a handover during apredetermined time period; information related to estimations of certainchannel properties, including dispersion or delay profile, that enablesthe wireless communication device to determine that it is stationary, bychecking whether these channel properties have remained constant duringa predetermined time period; information related to estimations of aDoppler spread that enables the wireless communication device todetermine that it is stationary, by checking whether the estimations ofthe Doppler spread; and information about the geographical position ofthe wireless communication device provided by a user equipment(UE)-internal global positioning system (GPS) receiver that enables thewireless communication device to determine that it is stationary, bychecking whether the information about the geographical positionprovides indications that the geographical position has remainedconstant during a predetermined time period.
 8. The method according toclaim 1, wherein information received in the beam sweep transmissioncomprises one or more of system information, paging information andother information that the wireless communication device needs tomonitor when in the first activity state.
 9. The method according toclaim 1, further comprising receiving information in the beam sweeptransmission comprising tracking area information instructing thewireless communication device to perform a tracking area update.
 10. Themethod according to claim 1, wherein the configuration information alsocomprises information about a sequence of beams used in the beam sweeptransmission.
 11. The method according to claim 1, wherein the beamsweep transmission is a periodic beam sweep transmission.
 12. The methodaccording to claim 11, wherein the configuration information furthercomprises the periodicity of the periodic beam sweep transmission. 13.The method according to claim 12, wherein the method comprisesdetermining a sequence of times to initiate reception of beam sweeptransmissions based on the obtained information, the configurationinformation and the periodicity of the beam sweep transmissions.
 14. Themethod according to claim 1, wherein the method comprises the furtherstep of returning to the first activity state after having receivedinformation in the beam sweep transmission.
 15. A wireless communicationdevice configured to receive information transmitted during a beam sweeptransmission, comprising: communication circuitry configured to receivethe information transmitted during a beam sweep transmission; andprocessing circuitry operatively associated with the communicationcircuitry and configured to: obtain information enabling the wirelesscommunication device to determine whether it is stationary; acquireconfiguration information comprising information about a starting timeof the beam sweep transmission; determine a time to initiate a receptionof the beam sweep transmission based at least partially on the obtainedinformation and the configuration information, thereby allowing thewireless communication device to enter, or remain in, a first activitystate until the determined time; and cause the wireless communicationdevice to enter, at the determined time, a second activity state,whereby the wireless communication device is prepared to receive thebeam sweep transmission; wherein the processing circuitry is configuredto, when the obtained information indicates that the wirelesscommunication device is stationary, determine the time to initiate thereception of the beam sweep transmission by determining the time basedon a time offset determined from an earlier beam sweep transmission, thetime offset being between the starting time of the earlier beam sweeptransmission and the reception by the wireless communication device of abeam of the earlier beam sweep transmission.
 16. The wirelesscommunication device according to claim 15, wherein the first activitystate is at least one of an idle state, a dormant state, an energysaving state and a non-receiving state, and wherein the second activitystate is a receiving state.
 17. The wireless communication deviceaccording to claim 15, wherein the processing circuitry is configured toacquire the configuration information by receiving a message comprisingthe configuration information.
 18. The wireless communication deviceaccording to claim 17, wherein the configuration information is receivedin a message transmitted from a radio network node that performs thebeam sweep transmission.
 19. The wireless communication device accordingto claim 15, wherein the processing circuitry is configured to determinethe time offset by comparing a time of reception registered by thewireless communication device with respect to the beam received in theprevious beam sweep transmission with the starting time as indicated inthe configuration information.
 20. The wireless communication deviceaccording to claim 19, wherein the processing circuitry is configured toobtain the information indicating whether the wireless communicationdevice is stationary by obtaining time offsets for at least twodifferent beam sweep transmissions and comparing the two different timeoffsets.
 21. The wireless communication device according to claim 15,wherein the processing circuitry is configured to obtain information inthe form of one or more of the following: information from a sensordevice about the position of the wireless communication device thatenables the wireless communication device to determine that it isstationary, by checking the information from the sensor device;information related to handovers of the wireless communication devicethat enables the wireless communication device to determine that it isstationary, by checking whether it was subjected to a handover during apredetermined time period; information related to estimations of certainchannel properties, including dispersion or delay profile, that enablesthe wireless communication device to determine that it is stationary, bychecking whether these channel properties have remained constant duringa predetermined time period; information related to estimations of aDoppler spread that enables the wireless communication device todetermine that it is stationary, by checking whether the estimations ofthe Doppler spread; and information about the geographical position ofthe wireless communication device provided by a user equipment(UE)-internal global positioning system (GPS) receiver that enables thewireless communication device to determine that it is stationary, bychecking if the information about the geographical position providesindications that the geographical position has remained constant duringa predetermined time period.
 22. The wireless communication deviceaccording to claim 15, wherein the information received in the beamsweep transmission comprises one or more of system information, pagingand other information that the wireless communication device needs tomonitor when in the first activity state.
 23. The wireless communicationdevice according to claim 15, wherein the processing circuitry isconfigured to receive information in the beam sweep transmissioncomprising tracking area information instructing the wirelesscommunication device to perform a tracking area update.
 24. The wirelesscommunication device according to claim 15, wherein the configurationinformation also comprises information about a sequence of beams used inthe beam sweep transmission.
 25. The wireless communication deviceaccording to claim 15, wherein the beam sweep transmission is a periodicbeam sweep transmission.
 26. The wireless communication device accordingto claim 25, wherein the processing circuitry is configured to acquireconfiguration information that comprises the periodicity of the periodicbeam sweep transmission.
 27. The wireless communication device accordingto claim 26, wherein the processing circuitry is configured to determinea sequence of times to initiate a reception based on the obtainedinformation, the configuration information and the periodicity of thebeam sweep transmission.
 28. The wireless communication device accordingto claim 15, wherein the processing circuitry is configured to returnthe wireless communication device to the first activity state afterhaving received the information in the beam sweep transmission.